Warped oven baking trays / roasting tins

Baking sheets or roasting tins may warp/deform when they are subjected to any stresses, extremely high/low temperatures or uneven heating in the sheet metal.

In rare cases baking sheets or roasting tins may deform/warp on heating and, after cooling, return to the original shape.

To avoid warped/deformed baking trays/roasting tins, place the baking tray evenly, use appropriate shapes for round pizzas or similar foods and place them on the grate, and if the recipe calls for a preheated oven, always preheat the oven without metal.